Research On Digital Watermarking Algorithm Based On DWT-SVD

Due to the rapid development of computer hardware and software technology,the transmission of digital works in various medium is very convenient and fast.The development of technology brings convenience,but also causes some troubles.For one thing,digital works are easy to be illegally copied and tampered with.Therefore,the copyright protection of digital works has become an urgent practical problem to be solved.In order to prevent digital works from being pirated,infringed and maliciously tampered with,people have proposed digital watermarking technology in combination with the characteristics of traditional cryptography authentication.Nowadays,it has developed into one of the important means of copyright protection for digital works.This paper mainly studies the key technology of digital watermarking of image carrier.The main points of work are summarized as follows:1.The watermark image is preprocessed using the Arnold scrambling algorithm.The block theory is introduced based on the SNR scrambling degree and the probability distance scrambling evaluation method respectively.The binary image with the size of 32x32 is experimentally analyzed.Combined with the human visual effect,the optimal block size of the evaluation method is determined.Using the obtained scrambling evaluation method,it is further proved that the higher the scrambling degree,the better the robustness of the digital watermarking system.2.Based on DWT-SVD technology,algorithms of non-blind digital watermarking and blind digital watermarking are proposed innovatively combined with the principle of hand up system.First,the watermark information is embedded in the LL,HL and LH sub-bands of the carrier image after discrete wavelet transform.Then,the weight values of LL?HL,and LH when the watermark is extracted are determined experimentally.Finally,the digital watermarking algorithm proposed in this paper is robust by image attack experiments.3.Based on MATLAB,a digital watermarking system is developed,which can realize the functions of reading the carrier image,reading the watermark image,embedding the watermark and extracting.